i know this isin't what i should do here but please help our server is about to get hacked please help Moobloom Kingdom

just ban them from the realm or server right? do /ban or /tempban username time for tempban ban = permant 

If this is a realms server, then please head over to the Realms bug tracker! If you're using a 3rd party server, make sure you contact the owner of your server, as Mojang is not affiliated with 3rd party server owners.

just use the command /ban meriheppu

only the admin or moderaters can ban someone